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Showing posts from August, 2022

How to prevent wear down of liner?

Use Low Sulphur oil. Maintaining high jacket water temperature. Running Main Engine at normal sea low , avoid running at low loads. Increase LO supply so that piston and liner seizure will not take place. By using proper TBN oil and correct grade of oil By avoiding ingress of moisture in charge air 

Unsafe condition, Unsafe act , Near miss and Accident

  Unsafe condition Unsafe condition mean any condition that could cause undue hazard to life , limb or health  of any person authorized or expected to be on or about the premises. Unsafe act An unsafe act is when an individual who has both knowledge and control of an existing unsafe condition or action , but choses to perform the action or ignore the condition . Generally perform unsafe acts in an effort to save time and /or effort Near Miss A near miss , near hit or close call is an unplanned event that has the potential to cause , but does not actually result in human injury , environmental or equipment damage or an interruption to normal operation. Accident An Accident is an unintended , normally unwanted event that was not directly caused by humans , the term accident implies that nobody  should be blamed , but the event may have been caused by unrecognized or unaddressed risks

CO2 extinguisher have no pressure gauge .Why

CO2 is a gas at room temperature until it is compressed to around 830psi at which point it begins to liquefy under that pressure .At that point the pressure will remain constant until the container is filled to its rated capacity(by weight) with liquid CO2. As long as there is some liquid CO2 in the container the pressure of the vapor above the liquid will remain at 830 psi.So a pressure gauge will show 830 psi without regard to the actual amount of liquid CO2 in the container

Induction hardening of crankshaft

It is a type of surface hardening in which a metal part is induction heated and then quenched . It increases the hardness and brittleness of the part . Induction hardening is used to selectively harden areas of a part or assembly without affecting properties of that part. Induction hardening is a non contact heating process which uses the principle of electromagnetic induction to produce heat inside the surface layer of workpiece . By placing a conducting material into strong magnetic field, electric current can be made to flow in the material by creating heat due to I2R losses in the material . In magnetic material , further heat is generated below curve point due to hysteris losses Advantages: Fast process No scaling  High wear and fatigue resistance Localized, constant and precise heating

Importance of Fuel pump

To time and meter the fuel accurately to the fuel injectors for combustion. Precise time of injection and constant same quantity delivered to each unit. Adaptability to change injection timing and quantity with load changes. Build up of fuel pressure from the very start to ensure atomization from the start and build of maximum power at the most desired point of the cycle for optimum peak pressure and cleaner emission.

Coupling Alignment

Coupling Alignment ( Temperature Adjustments ) :The operating temperature of a pump and a motor are often different. The motor will run at a specific temperature, which is usually indicated, on the motors data plate, and the pumps temperature will depend on the temperature of the fluid being pumped.  This change in temperature will cause the coupling to become misaligned at the units operating temperature. This situation has been compensated for. A few calculations will ensure that the coupling will be aligned when the pump is running.  The formula for this is Coefficient of expansion X temperature rise X centerline .  Coefficient of Expansion is the amount of expansion per unit length, per degree (F) rise or fall in temperature.  Temperature rise is the difference between ambient temperature and running temperature of the pump or motor. Ambient temperature is the surrounding temperature.  The center height is the center height of the pump and motor shafts.

NER and its location

NERs, sometimes called  Neutral Grounding Resistors , are used in an AC distribution networks to limit transient overvoltage that flow through the neutral point of a transformer or generator to a safe value during a fault event. In case of high voltage NER is used to reduce fault current. It is connected in between neutral to earth. If a generator is high voltage then it's neutral will be connected to earth via NER